Sharyathi Nagesh <sharyath at in.ibm.com> writes: > Hi > While testing with kexec tool, I observed some problems. When application > (kexec) is 32 bit and kernel is 64 bit I observed that loading crash kernel > works without any issues but unloading crash kernel fails. > -------------------------------------------------------- > running strace over 'kexec -u -p' > show the problem to be with sys_kexec_load() call > > sys_kexec_load(0, 0, 0, 0x1, 0) = -1 EINVAL (Invalid argument) > write(2, "kexec_load (0 segments) failed: "..., 49 > kexec_load (0 segments) failed: Invalid argument > ) = 4 Yes. This is a bug. Although not in the kernel implementation. > -------------------------------------------------------- > > This is patch to fix the problem, I think kernel code had a typo where in: > if((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH) was used instead of > if((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) Nope. We do the latter check after we have fixed up the arguments and call sys_kexec_load. The check really is meant to filter out KEXEC_ARCH_DEFAULT. > This patch takes care of that, I have tested the patch it worked fine for > me. Please review the patch and let me know of your views. This patch is based > on linux-2.6.26-rc3. That patch as it exists is actively bad. It removes the check for a really nasty gotcha if someone passes in KEXEC_ARCH_DEFAULT in 32bit mode. Code expecting a 32bit handoff and getting a 64bit handoff will explode in fun ways. You happened to test the one corner case where this does not matter. What we need to do is fix /sbin/kexec to pass in the correct architecture of the kernel for unload as it does for load. Eric
